msm8660: update audio policy

based off http://review.cyanogenmod.org/#/c/52982/

Change-Id: I8fdd2cec421e7b1b715c899c8d10b7a00261a2d4
msm8660: increase size of buffers to fit PROP_VALUE_MAX

Change-Id: I03f4f85a42c82816112513c15c2269e46e01954b